Process for producing isobutyl ethers



phenyl, dioctylphenyl, and the like. 'ene chain, (OC,,H if present, may be derived from United States Patent p 2,886,600 rnocnss FOR PRODUCING ISOBUTYL nrmzns Lee H. Horsley and Peter S. Petrie, Midland, Mich., as-

signors to The Dow Chemical Company, Midland, Mich., a corporation of Delaware No Drawing. Application March 29, 1957 Serial No. 649,295

19 Claims. (Cl. 260'-613) This invention relates to processes for making isobutyl ethers of hydroxy compounds. It particularly relates to, though it is not restricted to, the production of isobutyl ethers of glycol and polyglycol monoethers.

According to the invention, a compound containing one alcoholic or phenolic hydroxyl group is reacted with. v one mole of isobutylene oxide thus forming a 2-methyl-- R- OC,.H,. .o-cH on CH p 2 2'- a):

"ice

acetate, is pyrolyzed with or without a catalyst. The reaction maybe broadly represented by the equation wherein R, n and x are as before and y is 0 or 1.

In the preferred process, the ether-alcohol formed in Step 1 is acetylated, preferably by reaction with acetic anhydride, and the acetate is then pyrolyzed. The byproduct acetic acid can be recovered and recycled in the process.

The pyrolysis of the ether-alcohol or its ester may be conducted in either liquid or vapor phase and in the presence or absence of catalysts. It is obviously not practical to pyrolyze in the vapor phase those compounds having very high boiling points, such as polyglycol derivatives of high molecular Weight. Such materials, however, are easily pyrolyzed in the liquid phase.

The pyrolysis of the ether-alcohols themselves is catalyzed by the usual dehydration catalysts, such as silica, alumina, activated carbon, ceramic chips, broken glass and the like, activated carbon being the preferred cat alyst. In the pyrolysis of the ether-esters, catalysts exert only minor influence. However, it is advantageous to use a solid catalyst such as charcoal, Berl saddles and the like, since they have some catalytic eifect and also serve wherein R is a primary or secondary alkyl, aryl or alkaryl In Step 1, the oxyalkylation reaction, the conventional as heat transfer and equalization media.

Pyrolysis temperatures may be varied Widely, depending on the particular compound being pyrolyzed, the contact time, the catalyst, if any, and whether the reaction is vapor or liquid phase. In the preferred process of catalytic vapor phase pyrolysis, temperatures in the range 250-450 C., and preferably about 300400 are generally used. Contact times are usually about 5-60 seconds. In liquid phase pyrolysis, somewhat lower temperatures, about l00300 C., are generally used, together with longer contact times. The latter may vary from a few minutes to several hours, a preferred range beingv about 0.2 to 2 hours.

alkaline catalysts and reaction conditions are used. Acid catalysts cause the formation of the isomeric l,1-dimethyl-2-hydroxyethyl ether which is difficult to dehydrate, and also catalyze the isomerization of isobutylene oxide to isobutyralde'hyde. We prefer to use a strong alkali catalyst, such as the alkali metals, their oxides,

C. and pressures are in' the 'RIis aprirrrany or secondary alkyl group? containing up'to -22 carbon: atoms, such asbutyl; hexyl, dec'yl', dodecy-l,

tridecyl, hexadecyl, octadecyl-,ieicosyl, docosyl, isobutyl, sec.-butyl and capryl, or an aryl or. alkaryl group containing up to 22 carbon atoms, such as phenyl, cresyl,-

xylyl, naphthyl, butylphenyl, octylphenyl',dodecylphenyl, t'rid'ecylphenyl, phenylphenyl, cyclohexylphenyl, dibutyl- The polyoxyalkylkylene units upto about 50.

The dehydration reaction of Step 2 is preferably a therrnal'--cra'cking process in which either the ether-alcohol Reaction temperatures are Since isobutylene oxide reacts only C all with the product of Step 1, an

. It is sometimes advantageous to conduct the pyrolysis step under reduced pressure; In vapor phase pyrolysis this aids in the vaporization of materials of low volatility while in liquid phase pyrolysis it aids in the removal of volatile products of the pyrolysis.

Step 3, the hydrogenation of the olefinic compound produced in the pyrolysis step, is carried out with the usualcatalysts and conditions for the hydrogenation of olefinic materials. Suitable catalysts include platinum, palladium, nickel, and the like, the temperatures and pressures being those generally used with these catalysts. Thus, platinum is effective at room temperature and atmospheric pressure; palladium at 50-100 and 15-100 formed in Step 1 or an ester thereof, preferably: the I p.s.i.g. and nickel at -200 and 100-1000 p.s.i.g.

The practice of the invention is illustrated by the following examples.

STEP l.-OXYALKYLATION The hydroxy compound to'be oxyalkylated was placed in a suitable reactor having means for heating and agitating the contents; The alkali catalyst, usually potassium hydroxide, was dissolved in the hydroxy compound, air in the reactor was replaced with nitrogen, the temperature was adjusted to the desired point and isobutylene oxide was gradually added. When the reaction was substantially complete, as indicated by the pressure, the product was neutralized with carbon dioxide or acetic acid, stripped of unreacted isobutylene oxide and, where possible, purified by distillation. The extent of reaction of the hydroxy compound could be determined readily by thestandard 0H determination by reaction with tion in so far as possible.

4 B. Liquid phase cleavage The liquid was heated in a flask at or below atmospheric pressure and products were analyzed by distilla- Results of some typical experiments are summarized in Table IV.

The products were purified'by distillation if possible. The polyglycol ethers, being substantially non-volatile, were purified by vacuum stripping to remove volatile materials, caustic saponification to cleave esters and TABLE I.REACTION OF ISOBUTYLENE OXIDE WITH HYDROXY COMPOUNDS Mole Conver- Example Ratio, Time, Temp., Pressure, slon, Yield,-

No. Hydroxy Compound Oxide] Hrs. 0. p.s. .g. Hydroxy Percent Hydroxy Opd.,

Opd Percent Methanol 1. 07 -95 0 95 87 Isopropanol 1. 10 70 -88 0 68 62 x-Octyl alcohol b 1. 10 7 90-115 0 70 79 Phenol 1. 10 8 -125 0 100 84 Dl-sec.-Butylphenol 1. 10 12 95-125 0 100 51 1-Methoxy-2-PropanoL. 1. 20 30 90-125 0 65 89 1-Phenoxy-2-Propanol 1. 20 18 90-125 0 76 80 E-600 Methyl Ether 1. 25 1. 5 80-100 0 P-600 Methyl Ether 2. 2 18 75-125 0 88 P-600 Methyl Ether 1. 3 3 140-150 10-50 67 P-400 Butyl Ether- 3. 0 58 90-150 0 P-600 x-Octyl b Eth 2. 2 31 -150 0 85 P-350 Phenyl Ether" 3.0 34 90-150 0 99 P-500 x-Tridecyl b Eth 2. 5 40 90-150 0 84 P-500 Z-Ethylhexyl Ether 3. 0 72 90-150 0 90 P-5001,3-Dimethoxy-2-PropylEther. 2. 5 42 90-150 0 93 Yield of distilled mono-oxybutylated product based on hydroxy compound consumed.

Oxo process alcohol 0 E =polyoxyethylene glycol; P=polyoxypropylene glycol. Suflix numbers are average molecular weights.

TABLE lL-PHYSIOAL PROPERTIES Compound Bolllng N o.- Compound Point, Nn" a};

O./mm.

l-Methoxy-z-Methy1-2-Propanol -116/760 1. 4024 0. 8895 l-Isopropoxy-2-Methyl-2-PropanoL 133/760 1. 4029 0. 8512 1-0ctyloxy-2-Methyl-2-Propan 1.-- 118-124/20 1.4300 0. 8597 1-Phenoxy-2-Methyl-2-Propanol 120-126/20 1. 5112 1. 0284 1-(ll )l-sec.-ll3utylphenoxy)-2-Methyl-2- 165-168/10 1. 4948 0. 9408 ropano 1-(l-Methoxylsopropoxy)-2-Methyl-2-Pro- 178-187/760 1. 4172 0. 9265 pan 1- (l-Phlenoxyisopropoxy) -2-Methyl-2-Pro- 158-165/20 1. 4919 1. 0174 pano Acetate of No. 1 -143/760 1.4030 0. 9461 Acetate of N0. 2.- 160-164/760 1. 4033 0. 9043 Acetate of No. 3.. 5-138/20 1. 4259 0.8925 Acetate of N o. 4.- 136-139/20 1. 4900 1.0423 Acetate of No. 51- -178/10 1. 4846 0. 9584 Acetate of No. 6.- 96-101/20 1.4150 0.9600 Acetate of N o. 7 173-177/20 1. 4812 1. 0337 I Compounds listed are products from the corresponding examples 01' Table 1.

STEP 2.--DEHYDRATION A. By vapor phase pyrolysis The apparatus consisted of a 1" x 24" stainless steel 65 tube, electrically heated, the first 6" of which was packed with Berl saddles and used as a preheater and 18" of which were packed with the catalyst and.- constituted thev reaction chamber. In operation, the tube was heated to the desired temperaure and the compound to be, pyro- 70 lyzed was then pumped slowly into the preheater where it was vaporized. After passing through the' reaction chamber the products passed into a condenser-fromg which the condensate was collected and analyzed. Results .of some typical experiments are shown in Table HI.

water-washing to remove glycols, salts and any other water soluble impurity. Yields were based on analyses for olefinic unsaturation'in the products.

STEP 3.-I-IYDRO GENATION 75 TableV.

TABLE IIL-VAPOR PHASE PYROLYBIS Products Isolated, Mole Percent Contact Temp.,' Compound No.- Catalyst Time, C. Sec. Orig. Isobutyl Isobutyr- Methallyl I Opd. ene aldehyde Ether 55 2. 9 18 16 8 30 23 2 19 46 5 13 16 14 28 2 26 66 0 3 65 0 1 16 0, 4 s1 d 22 23 23 d 8 9 69 The compounds used were those having these numbers inlable II. b Old catalyst previously used in the process. A molar equivalent of acetic acid was mixed with the compound. 1 Contained large amounts of propylene.

TABLE IV.-LIQUID PHASE PYROLYSIS Products Isolated, Mole Percent Time, Temp., Press Compound N 0. Catalyst, g./mole hr. 0. mm.

Original Isobutyr- Methallyl Comaldehyde Ether pound Numbers are the same as in Tables I and II. b One molar equivalent 0 A sulfonic acid ion-exchange resin sold by the Dow Chemical Company.

4 An activated earth.

TABLE V.-HYDROGENATION OF METHALLYL ETHERS Time, Yield, Methallyl Ether Moles Cat., g. Hr. Percent of Theory Methyl l 0.25 1. 0 2 89 Phenyl 0. 10 1. 0 1 81 Dl-sec.-Butylpheny 0.10 0. 5 1 5 77 P-600 Methyl Ether 0. 22 2. 0 4 92 Toluene was used as a solvent. b Methyl methallyl diether 0t polyoxypropylene glycol of molecular weight 600.

The products produced by the process of the invention have a wide range of physical and chemical properties and uses, depending on their structure. Some physical properties of some of them are shown in Table VI.

TABLE TL-PHYSICAL PROPERTIES of acetic acid was mixed with the compound before pyrolysis.

Both the methallyl and the isobutyl ethers of the polyoxyalkylene glycol ethers were thick, non-volatile oils. The latter were excellent lubricants and hydraulic fluids having exceptional stability to heat and oxidation.

We claim:

1. A process for producing an isobutyl ether comprising (1) reacting isobutylene oxide with a hydroxy compound having the formula wherein R is a hydrocarbon radical selected from the group consisting of primary and secondary alkyl, aryl and alkaryl radicals containing up to 22 carbon atoms, n is an integer from 2 to 4 and x is an integer from 2 to 50, thus to form the 2-methyl-2-hydroxypropyl ether of the hydroxy compound; (2) dehydrating the said 2- methyl-Z-hydroxypropyl ether, thus to form the corresponding methallyl ether; and (3) hydrogenating the said methallyl ether, thus to form the desired isobutyl ether.

2. A process as defined in claim 1 wherein x is about 5 to 20.

3. A process for producing an isobutyl ether comprising catalytically hydrogenating a methallyl ether having the formula wherein R, n and x are as defined in claim 1, whereby the '7 methallyl ether is converted to the corresponding isobutyl ether.

*4. A process as defined in claim 1 wherein R is an alkyl radical.

5. A process as defined in claim 1 wherein n is 2.

6. A process as defined in claim 4 wherein R is a- 10. A process as defined in claim 4 wherein R is an octyl radical.

11. A process as defined in'claim 1 wherein R is an aryl radical.

12. A process as defined inclaim 11 wherein R is a wherein R, n and x are as defined in claim 1, comprising heating a compound having the formula 'wherein R, n and x are as before and y is an integer from 0 to l, at a temperature above that at which it is stable but below that at which the methallyl ether is unstable. 16. A process as defined in claim 15 wherein y is 0. 17. A process as defined in claim 15 wherein y is 1'- 18. A process as defined in claim 15 wherein the material being heated is in the vapor phase.

19. A process as defined in claim 15 wherein the material being heated is in the liquid phase.

References Cited in the file of this patent I UNITED STATES PATENTS 2,122,812 Groll et a1. July 5, 1938 2,327,053 Marple et a1. Aug. 17, 1943 2,671,112 Inhoffen et a1. Mar. 2, 1954 FOREIGN PATENTS 525,843 Canada June 5, 1956 

1. A PROCESS FOR PRODUCING AN ISOBUTYL ETHER COMPRISING (1) REACTING ISOBUTYLENE OXIDE WITH A HYDROXY COMPOUND HAVING THE FORMULA 